Our objective is to gain a better understanding of neural encoding in the auditory system as it pertains to animal communication by sound. Quantitative electrophysiological methods continue to form the core of our attack on these problems. We now plan to couple the electrophysiological work with behavioral investigations. A long term goal is that our findings will lead to the identification of principles of neural encoding which can be extended to the neural processing of speech in humans. We use computer techniques, behavioral methods, and the mathematics of communication theory in attempting to discern the coding of information in patterns of neural activity. Two projects are planned: 1) single-unit studies of cortical neurons in behaviorally trained monkeys, and 2) electrophysiological and behavioral studies of communication by sound in birds.